Method for enhancing soil growth using bio-char

ABSTRACT

A method is described for rendering char from a biomass fractionator apparatus (BMF char) suitable for addition to soil in high concentrations, the method relying on multiple processes comprising removing detrimental hydrocarbons from BMF char, removing adsorbed gases from BMF char, introducing microorganisms to the BMF char, and adjusting sail pH.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims the benefit of, U.S.patent application Ser. No. 13/154,213 filed Jun. 6, 2011, which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates generally to methods for soil enhancement,and more particularly to methods for enhancing soil growth utilizing ahigh surface area, porous char.

DESCRIPTION OF THE RELATED ART

As the world continues to increase in population, severe strains arebeing placed on natural resources. One problem relates to growing asufficient amount of food to feed an increasing world population. Agentsthat enhance soil growth are eagerly being sought to help in feedingthis growing number of people. Charcoal is one such agent, but its useso far has been rather limited. Charcoal production has been known andpracticed throughout the ages. Forest fires produce charcoal and thishas been found at times to be beneficial to the soil. Combustion of woodin oxygen-depleted atmospheres produces charcoal, which retainsnutrients but does not readily break down. Indeed, its mean residencetime in soil has been estimated at millennia. See, Cheng, C. H.,Lehmann, J, Thies, J E, and Burton, S. D. Stability of black carbon insoils across a climatic gradient. Journal of Geophysical ResearchBiogeosciences 113 (2008) G020227. Biochar can be an effective carbonsink and carbon sequestration agent as well as an agent for improvingagricultural output.

Several investigations have shown that biochar added to soil can enhancesoil growth under certain circumstances. For example, it has long beenknown that the Amazonian soil terra preta from Brazil consists of a mixof soil and charcoal that contains higher levels of plant nutrients thansurrounding soils. The Amazon soil is anthropogenic soil, the charcoalresulting from the combustion of wood in kilns along with combustion ofdomestic and agricultural refuse. Regular kitchen refuse and ash arealso deposited in the Amazon soil. Terra preta contains 9% biochar,whereas neighboring soils typically have a charcoal concentration ofless than 0.5%. Soil fertility has persisted in excess of hundreds ofyears. However, it has been difficult to replicate this soil elsewhere.Biochar addition has been shown to increase the bioavailability ofnutrients such as N and P. See, e.g., Lehmann J, DaSilva J P, Steiner C,Nehls T, Zech W, and Glaser W. Nutrient availability and leaching in anarchaeological Anthrosol and a Ferralsol of the Central Amazon basin:fertilizer, manure and charcoal amendments. Plant Soil 249 (2003)343-357. See also, Tryon E H. Effect of charcoal on certain physical,chemical, and biological properties of forest soils. EcologicalMonographs 18 (1948) 81-115. Under some circumstances, biochar has beenshown to provide extra nutrients itself. Some farmers practiceslash-and-char techniques in preference to more indiscriminateslash-and-burn soil management.

Previous attempts to incorporate high levels of biochar into soil havebeen ineffective in part because partial combustion leaves residualpoly-aromatic hydrocarbons (PAHs) within the char. The PAHs areco-produced with the biochar and are adsorbed within the biochar. See,Preston, C. M. and Schmidt M. W. I. Black (pyrogenic) carbon: Asynthesis of current knowledge and uncertainties with specialconsideration of boreal regions. Biogeosciences 3 (2006) 397-420. Thesehydrocarbons inhibit seed germination and repel microorganisms that areessential to soil growth such as fungi and bacteria. Although certainfungi are known to degrade PHAs in soils, it can take weeks for thedegradation to start because the fungi are not able to colonize suitableenvironments. Approximately 80% of vascular plant families are colonizedby arbuscular mycorrhizal (AM) fungi. These fungi are obligate symbiontsand take up the plant's photosynthetic products in the form of hexoseswhile providing a high surface area network for the plant uptake ofnutrients, especially phosphorus. Carbon produced from fossil fuels(e.g., coal, tar sands, petroleum) contains toxic compounds and it isnot cost effective to remove or filter out these compounds. As a result,carbon from these sources is generally unsuitable for soil addition.

US Patent Publication No. 2010/0040510 discloses a multistagepressurized fluidized bed gasifier operating between 780° C. and 1100°C. that converts biomass to syngas and biochar. The biochar is said tobe capable of being added to soil. US Patent Publication No.2008/0317657 provides a system and method for sequestering carbon in theform of char added to soil; the char is created by gasifying biomass inan unspecified reactor vessel. A low heating value producer gas is aby-product of the process. US Patent Publication No. 2004/0111968discloses pyrolyzing biomass in an unspecified reactor to produce charand pyrolysis gases, which are steam reformed to hydrogen. The char istreated with unspecified nutrients to become a carbon based fertilizer.US Patent Publication No. 2010/0300866 details a method for convertingpyrolyzable organic matter to biocarbon involving the recirculation ofcollected volatile vapors.

U.S. Pat. No. 6,811,703 teaches using a solid phase mixed solventpolymer as a soil amendment for removing and retaining solvated organiccompounds and inorganic ions from water sources, as well as adhesivelycoating the polymer onto sand along with at least one ion exchangematerial. The solid phase mixed solvent polymer is said to improveorganic leachate adsorption, and better retention of nutrients in thesoil by providing additional ion exchange network for the soil. The ionexchange is said to be a favorable mechanism for fertilizer ionretention within the exchanger, followed by a slow release to the roots.Clays have also been added to enhance soil growth. A problem with thisapproach is that upon exposure to water, the clay swells and soil poresbecome clogged.

BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION

The above methods of modifying biochar to enhance soil growth differsubstantially from the methods set forth in the following embodiments ofthe invention. These embodiments utilize a novel type of char (referredas BMF char) that is generated according principles delineated inco-owned, co-pending U.S. patent application Ser. No. 13/103,905, titled“Method for Biomass Fractioning by Enhancing Thermal Conductivity,” thecontent of which is incorporated herein by reference in its entirety.This patent application teaches systems and method for generating BMFchar using a biomass fractioning reactor in which biomass is fractionedinto thin sheets that are subjected to specific temperature ramps andpressure shocks.

Embodiments of the present invention disclose a novel process forrendering the BMF char suitable as a soil growth agent. This process maycomprise several steps including: (i) creating the BMF char, (ii)expelling detrimental agents within the BMF char, (iii) rendering theinternal surface area of the BMF char hydrophilic, and (iv) addingsuitable nutrients and microorganisms to the BMF char. In addition toacting as a soil enhancing agent, the BMF char can sequester carbon forlong periods of time. An alternate method for carbon sequestration viacoal production from biomass is disclosed in co-owned, co-pending USPatent Publication No. 2010/0257775, titled “System and Method forAtmospheric Carbon Sequestration,” the content of which is incorporatedherein by reference in its entirety.

Some embodiments of the present invention involve an agent for enhancingsoil growth that utilizes a novel char derived from a biomassfractioning system.

Further embodiments of the present invention involve a method forprocessing BMF char to be readily serviceable for soil amendment.

Additional embodiments of the present invention involve a method forsequestering carbon for long periods of time.

A particular embodiment of the invention is directed toward a method forthe production of an agent for enhancing soil growth, comprising: (i)grinding a biomass feedstock to produce ground biomass particles; (ii)subjecting the ground biomass particles to sequential or concurrentramps of temperature and pressure shocks; (iii) selectively collectingat least one volatile component as it is released from the groundbiomass particles; (iv) collecting a last remaining nonvolatilecomponent comprising BMF char; (v) rendering a surface of the BMF charhydrophilic; (vi) exposing the BMF char to microorganisms; and (vii)adding the BMF char to soil.

According to some implementations, the biomass particles are ground to adiameter between about 0.001 inch and about 1 inch. The method mayfurther comprise dispensing the ground biomass particles into thinsheets whose total thickness is a multiple of the ground biomassparticle diameter before subjecting the ground biomass particles tosequential or concurrent ramps of temperature and pressure shocks. Insome case, the multiple may be any real number in the range of 1 to 30.The biomass feedstock can be used to produce different BMF chars basedon a composition of the biomass feedstock. Pressure shocks may vary inmagnitude from 0.2 MPa to 10 GPa, and an admixture of pressure shocks ofdiffering magnitudes can be combined with pressure shocks applied over arange of times.

In some embodiments, the temperature ramp includes a sufficiently hightemperature to create a nonvolatile carbonaceous material within theground biomass particles. In addition, the pressure shocks can increasethermal conductivity of formed nonvolatile carbonaceous material withinthe ground biomass particles. The pressure shocks may also decrease theeffective density of the ground biomass particles. In some cases, thetemperature ramps and pressure shocks are conducted in an atmospherecontaining a supercritical fluid. In further embodiments of theinvention, a pH of the BMF char can be controlled via pH adjustmentagents. In various embodiments, the BMF char may be activated and a pHof the soil modified to accept the addition of BMF char.

According some implementations of the above method, the surface of theBMF char is rendered hydrophilic by removing adsorbed gas within charpores, wherein the surface of the BMF char is rendered hydrophilic byhigh temperature removal of adsorbed hydrocarbons. In some embodiments,adsorbed gases are removed by water infiltration, vacuum suction,ultrasonic means, or impact means. In other embodiments, adsorbed gasesare removed by introducing a water solution containing soluble plantnutrients. According to various embodiments of the invention,microorganisms can include members of at least one of fungi, bacteria orarchaea. In some cases, fungi are selected from members of the phylaGlomeromycota and the BMF char contains glomalin structures.

Other features and aspects of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate, by way of example, the featuresin accordance with embodiments of the invention. The summary is notintended to limit the scope of the invention, which is defined solely bythe claims attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The drawings are provided for purposes of illustration only andmerely depict typical or example embodiments of the invention. Thesedrawings are provided to facilitate the reader's understanding of theinvention and shall not be considered limiting of the breadth, scope, orapplicability of the invention. It should be noted that for clarity andease of illustration these drawings are not necessarily made to scale.

FIG. 1 is a flow diagram depicting a process for rendering biocharsuitable as a soil enhancing agent, in accordance with an embodiment ofthe invention.

FIG. 2 a is a flow diagram illustrating the generation of BMF char frombiomass, including an optional activation step, whereas

FIG. 2 b is a flow diagram illustrating the basic operational principlesbehind the conversion of biomass into BMF char, in accordance with anembodiment of the invention.

FIG. 3 is a diagram illustrating an example of applied pressure andcorresponding biomass pressure and temperature within the reactionchamber, as well as anvil position during this time interval, inaccordance with an embodiment of the invention.

FIG. 4 is a flowchart illustrating an embodiment of the stepwisedecomposition of biomass and accompanying formation of BMF char, inaccordance with an embodiment of the invention.

FIG. 5 is an SEM image of BMF char from corn, while

FIG. 5 b is an SEM image of char from corn activated with steam.

FIG. 6 a is a diagram illustrating growth of lettuce plants in soilscontaining different concentrations of char treated according to amethod of the present invention, whereas

FIG. 6 b-6 c are images depicting growth of plants in pH-adjusted soilsand nutrient-washed soil containing varying amounts of woodchar andsand.

FIG. 7 a is an SEM image of BMF char, while

FIG. 7 b is an SEM image of BMF char colonized by a commercial composttea mixture.

The figures are not intended to be exhaustive or to limit the inventionto the precise form disclosed. It should be understood that theinvention can be practiced with modification and alteration, and thatthe invention be limited only by the claims and the equivalents thereof.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

Embodiments of the invention are directed toward methods for enhancingsoil growth utilizing a high surface area, porous char. In someembodiments, the char is made using a method that modifies biomass tohave a hydrophilic surface and to exhibit a hospitable environment forbacteria, archaea and fungi necessary for plant growth.

FIG. 1 illustrates the basic steps for the creation of a novel biocharthat is modified to act as a soil growth enhancement agent, inaccordance with an embodiment of the invention. The initial stepcomprises a BMF char generation process 600 in which BMF char is createdfrom biomass, for example using a biomass fractionator. The subsequentsteps involve a process 610 for removal of detrimental hydrocarbons fromthe BMF char, a process 620 for removal of adsorbed gases from the BMFchar, an optional process 630 for introducing soluble nutrients into theBMF char, a process 640 for adding a compost agent to the BMF char, aprocess 650 for adjustment of soil or BMF char pH, and a process 660 formixing the BMF char with soil. The full nature of the invention willbecome evident from the following description of each step.

Bio-Char Generation

The basic principles behind bio-char generation (process 600) aredisclosed in co-owned, co-pending U.S. patent application Ser. No.13/103,905 entitled “Method for Biomass Fractioning by Enhancing ThermalConductivity,” the content of which is incorporated herein by referencein its entirety. The following is a possible embodiment for bio-chargeneration. Referring now to FIG. 2 a, biomass 40 is optionallypretreated in process 41 and loaded piecemeal onto a plurality ofmovable biomass reaction chambers 51 movable by common drive mechanismssuch as gear drives, chain drives, ratcheting sprockets, etc. Thereaction chambers 51 may be arranged on a disc that can rotatecontinuously or in a stepwise fashion. The pretreatment may comprise adrying step or other steps.

As used herein, the term ‘biomass’ includes any material derived orreadily obtained from plant sources. Such material can include withoutlimitation: (i) plant products such as bark, leaves, tree branches, treestumps, hardwood chips, softwood chips, grape pumice, sugarcane bagasse,switchgrass; and (ii) pellet material such as grass, wood and haypellets, crop products such as corn, wheat and kenaf. This term may alsoinclude seeds such as vegetable seeds, sunflower seeds, fruit seeds, andlegume seeds. The term ‘biomass’ can also include: (i) waste productsincluding animal manure such as poultry derived waste; (ii) commercialor recycled material including plastic, paper, paper pulp, cardboard,sawdust, timber residue, wood shavings and cloth; (iii) municipal wasteincluding sewage waste; (iv) agricultural waste such as coconut shells,pecan shells, almond shells, coffee grounds; and (v) agricultural feedproducts such as rice straw, wheat straw, rice hulls, corn stover, cornstraw, and corn cobs.

With further reference to FIG. 2 a, the biomass 40 may be ground by avariety of techniques into a particle size suitable for dispensationinto the reaction chamber 51. Particle size may range from 0.001 inch to1 inch in diameter, limited by processing equipment size and thermaltransfer rates.

Embodiments of the invention feature a biomass chamber 51 that is muchwider and longer than it is thick. In some cases, biomass is dispensedinto thin sheets whose total thickness is 1 to 30 times the biomassparticle size. A preferred thickness for the chamber for uncompressedbiomass (which is ground or chopped to ⅛″ or smaller) is approximately¾″ in thickness. As the biomass is heated and further pulverized (asdiscussed below), the emerging BMF char 52 quickly condenses to a layerabout 1/10″ thick. This aspect ratio ensures mild pyrolyzing conditionsthat allow the collection of useful chemical compounds known asbio-intermediary compounds as well as the production of BMF char 52. Aperson of skill in the art will appreciate that these biomass chambers51 can be sized in width and length along with the diameter of theircorresponding drive disc to any such size as appropriate for the desiredthroughput for the biomass fractionator, without departing from thescope if the invention.

Referring to FIG. 2 b, the ground biomass is subjected first to aheating profile ΔT1, typically a linear temperature ramp, by a heatingagent such as a metal anvil at processing station 58. In some cases, thepurpose of this first ΔT1 profile is to dewater the biomass. SubsequentΔTn profiles end at progressively higher temperatures and have thepurpose of outgassing and thermochemically converting biomass intouseful bio-compounds with progressively higher devolatilizationtemperatures. In order to accomplish this devolatilization in aselective manner, the temperature treatment is accompanied by a pressuretreatment. Compacting station 59 (e.g., comprising a series of anvils)subjects the biomass to accompanying pressure profiles, ΔPn, whichcomprise a sequence of pressure shocks that exploit the inherentcompressional features of carbon.

In some embodiments, the temperature profiles are linear ramps rangingfrom 0.001° C./sec to 1000° C./sec, and preferably from 1° C./sec to100° C./sec. By way of example, processing heating station 58 may beheated by electrical heating elements, direct flame combustion, or bydirected jets of heated working gas or supercritical fluid. The heatingprofile and the pressure compaction profile may be linked via a feedbackloop and may be applied by the same agent simultaneously. Compactingstation 59 may be controlled by electrically driven devices, aircompressed devices, or any other form of energy that serves to impactload the biomass. BMF char 52 remains after these processing steps. Itmay then be optionally activated by reacting it via process 53 withoxygen, methane, carbon dioxide or steam at high temperatures to createan ultra high surface area porous material 54.

The selective pyrolysis of the biomass 40 arises out of the interplaybetween the applied pressure pulses, applied temperature and resultantpressures and temperatures experienced by the biomass. The process isillustrated diagrammatically in FIG. 3, which shows applied pressure,biomass temperature, biomass pressure and anvil position as a functionof time. It is understood that a wide variety of different types ofpressure pulses may be applied, and that the entire illustration is apedagogic device. In FIG. 3, pressure shocks applied via compactingstation 59 are shown as a series of triangular pressure pulses with anunspecified rest time. The process starts out by utilizing the thermalconductivity of water. The biomass is first subjected to a temperatureramp sufficient to cause the biomass to release water. The releasedheated water vapor is then subjected to a pressure shock whichcompresses the steam, thus accelerating the biomass decomposition. Itmay be possible for the steam to attain supercritical form, though thatis not a requirement for the present invention.

A short time after peak pressure is applied, the anvil is pushed back bythe pressure of extracted volatile compounds. When the volatilecompounds are removed along with the steam, pressure within the biomassis decreased suddenly. Biomass temperature rapidly returns to baselevels, and the anvil returns to its un-extended base position. Afterthe water has been removed entirely from the biomass, the appliedtemperature causes hot localized areas within the biomass which initiatecarbon formation. In turn, compressive impacts on the newly formedcarbon increase the thermal conductivity of the carbon. The increasedthermal conductivity serves to efficiently transmit heat energy neededto break down the biomass to the next stage in its decomposition.Furthermore, because carbon exhibits compressional memory, compressiveimpacts are sufficient to exert this effect on thermal conductivity.

The compressional memory of carbon has been indirectly demonstrated instudies of commercial carbon resistors as low pressure gauges. SeeRosenberg, Z et al International Journal of Impact Engineering 34 (2007)732-742. In these studies, metal discs were launched from a gas gun athigh velocity and impacted an epoxy or Plexiglas target in which acarbon resistor is embedded. Resistance changes were measured as afunction of time after impact. It was noted that the resistancedecreased rather rapidly in less than a microsecond, and stayed low forseveral microseconds, in some cases over 10 microseconds, until it beganto increase gradually to pre-impact levels. There is essentially amemory effect or a slow relaxation after the impact. As electricalresistance and thermal conductivity are inversely correlated for carbonas for metals (See, for example, Buerschaper, R. A. in Journal ofApplied Physics 15 (1944) 452-454 and Encyclopedia of ChemicalTechnology, 5th edition), these studies reveal a compression memory onthe part of the carbon. This compression memory is at least partlyutilized in embodiments of the invention.

Embodiments of the invention also utilize the increase in thermalconductivity as carbon is compressed. The change in electricalresistance with pressure in carbon microphones is a well-known effectutilized by carbon telephones and carbon amplifiers. U.S. Pat. No.203,016, U.S. Pat. No. 222,390 and U.S. Pat. No. 474,230 to ThomasEdison, describe apparatus that transform sound compressions(vibrations) to changes in electrical resistance of carbon granules.Carbon is even more sensitive than most metals in its inverserelationship between electrical resistance and thermal conductivity.Below are data indicating the thermal conductivity of various substances(CRC Handbook of Chemistry and Physics, 87th edition) in comparison tothe measured thermal conductivity of BMF char:

TABLE 1 Select Thermal Conductivities in W/(m · K) Material ThermalConductivity Copper 390 Stainless Steel 20 Water 0.6 Dry Wood 0.3 Fuels0.1 to 0.2 Carrier Gases (H₂, N₂, etc.) 0.01 to 0.02 Carbon Char 0.01 to0.05 BMF char 1 to 5

As the thermal conductivity of the formed carbon within the biomassincreases due to pressure shocks, it becomes consequently easier toattain mild pyrolysis conditions within the biomass. As highertemperatures are reached, the fact that carbon is a better heat transferagent than water enables higher boiling compounds to become volatile.Pressure shocks serve to compress these higher boiling compounds andcontribute to fracturing cell walls within the biomass. The process isillustrated by FIG. 3 which shows anvil extension at peak pressuregetting longer with subsequent pulse application, thus indicatingsuccessive biomass pulverization in conjunction with release of usefulhigher boiling compounds.

A variety of pressure profiles ΔPn are effective in increasing thecarbon thermal conductivity. The magnitude of the pressure can vary from0.2 MPa to 10 GPa and may be applied via a number of differenttechnologies, including air driven pistons, hydraulically drivenpistons, and explosive driven devices. The duration of the pressureapplication can vary from 1 microsecond to 1 week. It is understood thatpressure pulses of different magnitudes and different time durations maybe admixed to yield optimum results.

The efficient heat energy transfer executed by embodiments of thepresent invention can be enhanced by the addition of supercriticalfluids in the reaction chamber. It is known that supercritical fluidscan improve heat transfer as well as accelerate reaction rates. Certainembodiments can operate with supercritical carbon dioxide, supercriticalwater, supercritical methane, supercritical methanol, or mixtures of theabove. It is possible that supercritical conditions are createdinternally with some pressure and temperature profiles.

BMF char 52 remains after these processing steps. The physicalcharacteristics of the char will differ depending on the startingbiomass material, which can include any of the above-identifiedmaterials such as wood, grasses, municipal solid waste, etc. Differentbiomass feedstocks are expected to produce different types of BMF chars,varying in porosity and other physical characteristics. The biomassfeedstocks can be fed individually or as mixtures of differentfeedstocks to produce chars containing different physicalcharacteristics.

After the BMF char is formed, a last processing step is to transfer theBMF char out of the reaction chamber for a subsequent storage or fillinginto a bio-char reactor for subsequent optional activation 53. Thetransfer may be accomplished via any number of mechanical means,including a press bar outfitted with a scraping knife.

FIG. 4 illustrates an embodiment of the stepwise decomposition ofbiomass and accompanying formation of BMF char using the principlesoutlined above. Referring to FIG. 4, dried biomass 90 is provided in theform of wood chips containing extractives, lignins, hemicellulose, andglucans. Operation 92 involves a size reduction wherein the biomass isground to 1/16″ size and placed on rotating pallets in a chamberapproximately ¾″ thick. Within the biomass fractioning reactor 94, thebiomass is subjected to a temperature ramp of 25° C./sec in anoxygen-free atmosphere for varying amounts of time with intermittentpressure shocks of 80 MPa lasting for 2 seconds with a 50% duty cycle.The following distribution 96 of devolatilized compounds was observed:

TABLE 2 Distribution of Devolatilized Compounds Fractionator StageVolatile Compound Char Formed Temperature n = 1 H₂O and H₂O solubleimpurities 100-150° C. n = 2 Lipids BMF Char (2) 150-250° C. n = 3Furfurals and other furans BMF Char (3) 250-375° C. n = 4 Ethane,Propane, Butane, Pentane BMF Char (4)  375-00° C. and respectivefragments n = 5 CO, H₂, Methane, Ethane BMF Char (5)   >500° C.

In addition to showing devolatilized components, FIG. 4 also shows theresultant BMF char 100 and possible catalytic conversion ofdevolatilized organic components to various liquid fuels 98 such abiodiesel, hydrocarbons, aromatics, jet fuel, BTX, light hydrocarbons,gasoline, diesel, methanol, and DME. The organic chemicals 96 can alsobe useful on their own as co-produced chemicals. By contrast, typicalpyrolysis processes do no exhibit a clear volatilization profile asshown above.

BMF Char Activation

The BMF char is preferably activated prior to use. Activation is awell-known procedure for increasing char surface area and adsorptivecapabilities. See, for example, Lima, I. M. et al, in Journal ofChemical Technology and Biotechnology, vol. 85, (2010), pp. 1515-1521.The activation step is an optional pretreatment and selective combustionstep which aims to create additional surface area to acceleratesubsequent desired reactions. Typical activating agents include CO₂, H₂Oand O₂. Table 2 shows data acquired using different activation agents at900° C. for BMF char generated using a biomass fractioning reactor. Inthe case, the BMF char was derived from corn cobs.

The increased surface area of the BMF char upon activation comes at theexpense of a loss of material, which serves to create a porous structurewithin the char. Whether exposed to oxygen or methane and air, a loss ofapproximately 40% of the initial weight was measured. Activationprocedures can produce surface areas in excess of 500 m2/g.

TABLE 3 Effect of Activating Agent on BMF Char Char ActivationActivation Activation BMF Char Activated Source Agent Time Temp ° C.Loaded, g BMF Char, g Corn Cobs O₂ 3 Hours 900 47.5 29 Corn Cobs CH₄,air 3 Hours 900 46 29.5

An SEM micrograph of unactivated BMF char derived from corn cobs isdepicted in FIG. 5 a, while FIG. 5 b is an SEM micrograph of corn cobschar after steam activation at 900° C. This material had a measured BETsurface area of 760 m2/g and an average pore size of 45 Å, whereasunactivated material typically yields BET surface areas below 100 m2/g.

Due to a different processing history, the BMF char arising out of thisbiomass fractioning process is different from carbonaceous depositsformed from pyrolyzers or coke from petroleum plants. A system capableof embodying the method of the present invention is described inco-owned, co-pending U.S. Patent Application No. 2010/0180805 entitled“System and Method for Biomass Fractioning,” the content of which isincorporated herein by reference in its entirety. This system comprisesa biomass load and dump station, a heated pulverizing processing stationfor compressing the biomass, a biochar dumping station for removingresidual biochar and a plurality of biomass reaction compartments ableto carry the biomass from station to station.

Removal of Hydrocarbons

Typical charcoal contains a variety of hydrocarbons in various stages ofdecomposition, depending on the last temperature to which the charcoalwas subjected. In a typical carbonization of wood, different stages ofvolatilization are reached depending on the temperature. During theearly stages of heating, wood releases water vapor as it absorbs heat.Wood decomposition starts above 110° C., yielding primarily CO, CO₂,acetic acid, methanol and minor traces of other components. Exothermicdecomposition starts around 280° C. and tar starts to form. Just above400° C., the wood has been essentially converted into charcoal, but thischarcoal still contains about ⅓ of its weight in tar material. Furtherheating is needed to drive off the tar. Because of the highly porousnature of wood, it is difficult to remove tar unless sufficiently hightemperatures are reached beyond the equilibrium decompositiontemperature of tar components.

The methods described herein differ substantially from typicalcarbonization in that mild pyrolysis is used to obtain a variety ofuseful volatile compounds, thus minimizing tar formation. The resultantBMF char is substantially different from typical charcoal in morphologyand residue. Small amounts of hydrophobic hydrocarbons, in particularpolyaromatic hydrocarbons (PAHs), can inhibit colonization of the BMFchar by microorganisms. The first step in rendering the BMF charhospitable for subsequent microorganism invasion is to expel thesehydrophobic hydrocarbons. Temperatures above 700° C. are required toremove the hydrophobic hydrocarbons from the BMF char walls. Thehydrocarbon removal step may be combined with the activation step.

Removal of Adsorbed Gases from Char Pores

The next step in rendering the BMF char more hydrophilic involvesremoving adsorbed gases within the BMF char pores to allow waterinfiltration. This is important because the BMF char can be a highsurface area compound (typically in excess of 300 m2/g in activatedform) which contains significant amounts of strongly adsorbed gaseswithin its pores. These gases are strongly adsorbed on pore surfaces andremoval is highly beneficial. A simple method for removal of adsorbedgases is to immerse the BMF char in boiling water. This may be referredto herein as the “wetting step.”

Optional soluble nutrients may be introduced during or after the wettingstep. The nutrients enter into a high surface area porous environmentand can exchange with adsorbed gases to some degree. Nutrients caninclude macronutrients containing nitrogen, phosphorus, potassium,calcium, magnesium, and sulfur as well as micronutrients containingmolybdenum, zinc, boron, cobalt, copper, iron, manganese and chloride.The high surface area, porous BMF char affords plants access torelatively significant amounts of nutrients. Additionally, the BMF charretains these nutrients at times when rainfall tends to wash them offfrom the soil in the absence of BMF char. Besides water infiltration,other methods include ultrasonic, vacuum and impact removal of air.

Addition of Beneficial Microorganisms

Once wetted, the BMF char is ready to accept beneficial microorganisms.These microorganisms may comprise fungi, archaea and bacteria, whichsupply nutrients to plants symbiotically. The microorganisms may beintroduced in a number of different ways, including mixing the BMF charwith compost and water, adding compost tea to the BMF char, blending thelatter with compost, or blending the BMF char with potting soil. Inembodiments using a compost tea, the product may be purchased atsuppliers such as Bu's Brew Biodynamic Tea® (Malibu Compost Inc, SantaMonica, Calif.), Nature's Solution Compost Tea® (Nature's TechnologiesInternational LLC, Novato, Calif.) or MycoGrow® (Fungi Perfecti, Inc.,Olympia, Wash.). The compost tea may be agitated to maintain an optimumoxygen concentration for microorganisms to thrive. Electric bubblingaerators, porous stones, or manual stirring are suitable methods tomaintain sufficient aeration. Different compositions of fungi, archaeaand bacteria may be used, depending on target soil.

A particularly beneficial fungi is the arbuscular mycorrhizal fungi,which expresses the glycoprotein glomalin on their hyphae and spores.These fungi are members of the phyla Glomeromycota. This protein helpsto bind soil particles together and is responsible for good soil filth.When introduced into biochar, the fungi will express glomalin within thebiochar pores and aid in maintaining good soil structure by binding thebiochar to soil particles. Additionally, the root structure provided bythe hyphae allows nutrients to penetrate in and out of the high surfacearea environment provided by the biochar.

Adjustment of Soil pH

It has been long been recognized that soil pH is an important variablein maintaining soil health and productivity. Soil pH tends to modify thebioavailability of plant nutrients. Some soils are inherently acidic orbasic in nature and a soil amendment needs to consider its effect onsoil acidity. Biochar can differ in its effect on soil pH depending onthe biomass source of the biochar. By way of example, the decompositionof corn cobs leaves significant amounts of K₂O in the biochar residue,which tends to render the biochar basic. Addition of this basic biocharto a soil that is already basic is detrimental to the soil. pHmanagement has been practiced inadvertently by Amazon Indians increating terra preta soils. Other materials are always present withcharcoal in terra preta soils, such as bones, fired clay bits and woodash. These materials buffer the acidic Latrelite soils. The bones andwood ash balance the pH of the acidic clay soils.

Soil pH can be managed in several ways, including: (i) shifting soil pHby adding pH adjusting compounds directly to the soil after BMF charaddition; (ii) adding additives to the BMF char that can shift the BMFchar pH; and (iii) adding BMF char directly to the soil and allowing itto self-neutralize for extended periods of time.

The first approach utilizes well known pH adjustment reactants appliedto soil. Neutralization compounds useful for acidic biochar can includeanions selected from the group of: bicarbonates, carbonates, hydroxides,amines, nitrates, halides, sulfonates, phosphates, and carboxylates.These compounds may comprise one or more functional groups within apolymer, as well as oxides such as calcium oxide and magnesium oxide,which produce basic compounds upon exposure to air. Neutralizationcompounds useful for basic biochar can include inorganic acids such asHCl, H₃PO₄, and H₂SO₄, and organic acids such as humic, vanillic andferulic acids. A dispersant may be optionally used.

Regarding the second approach, any of the compounds listed in the firstapproach may be applied directly to the BMF char. Additionally, BMF charmay be made less alkaline by impregnating it with bacterial compost tea(vide infra) containing acidic ingredients such as molasses, plantjuice, or algal extractives. The biochar may be made more alkaline byaddition of alkaline agents such as lime, bones, potassium carbonate orpotassium hydroxide. Buffering agents may also be added. The thirdapproach requires mere long term exposure to the atmosphere toneutralize via carbonic acid formation.

Mixing Soil and Biochar

A wide variety of different techniques exist for applying the BMF charto soil. The incorporation of BMF char into soil may be accomplished viaBMF char integration into traditional farm machinery, such as the use ofmanure or lime spreaders in conjunction with plowing methods utilizingrotary hoes, disc harrows, chisels, etc. Banding methods which allow BMFchar use without significantly disturbing the underlying soil may alsobe used. The BMF char may be mixed in solid form along with manure,compost or lime, or mixed with water or liquid manure and applied as aslurry. It may also be mixed with topsoil or applied directly to an areawhere tree roots will extend.

Illustrative Example 1 Effect of Char Concentration

FIG. 6 a shows plantings of Black Seed Simpson lettuce in soilscontaining different concentrations of steam activated corn char madehydrophilic via the above-described methods. The corn char had a BETsurface area of 760 m2/g (depicted in FIG. 5 b). The data shown is 8days after planting. Char pH was adjusted to 8.2 via seltzer water. Fromleft to right, FIG. 6 a shows data from lettuce grown in soilscontaining 100% sand, 10% char and 90% sand, 20% char and 80% sand, 30%char and 70% sand and 40% char and 60% sand (by volume). The char waswashed with Dyna-Grow® nutrients prior to use. It is shown in this casethat soils containing even 30% char allow lettuce growth; however,inhibition of soil growth is evident for the 40% and the 50% char soils

Illustrative Example 2 Effect of Nutrient Washing

FIGS. 6 b and 6 c demonstrate the effect of nutrient addition on thegrowth of Black Seed Simpson lettuce plants grown in soils containingdifferent char concentrations. The char was derived from unactivatedwood chip made hydrophilic via hydrocarbon expulsion and removal ofadsorbed gases. The char exhibited a pH around 9 when wet. Inparticular, FIG. 6 b shows nine plantings, all containing no externalnutrient addition. The first row shows experiments with soil containing10% char and 90% sand by volume, except for the potting in the middlewhich contains 100% sand. All the pottings on the left were subjected toa pH adjustment by nitric acid, adjusting the pH close to neutral. Allthe pottings on the right were subjected to a pH adjustment by bufferedseltzer bringing the pH to around 8. The second row shows two pottings,both containing soil comprised of 20% char and 80% sand by volume. Thethird row shows pottings with 30% char and 70% sand, and the fourthshows potting with 40% char and 60% sand. It is evident that plantgrowth is occurring even for soils containing the highest concentrationof char, and that this growth is similar for both types of pHadjustments. FIG. 6 c demonstrates similarly treated soils and pHadjustments, except for the addition of commercially available plantnutrients for all samples. It is observed that soil growth again occursfor all soil compositions, and that the growth is enhanced due to theaddition of nutrients.

Illustrative Example 3 Introduction of Microorganisms Into Biochar

In a two-gallon plastic container, 5 liters of distilled water arepoured and aerated with an electric motor for 1 hour in the presence ofa porous stone. 6 ml of molasses (Grandma's Molasses®, B&G Foods, Inc.)are then added along with 4 grams compost ingredient (Mycrogrow®, FungiPerfecti Inc.) containing the following mixture of fungi and bacteria:

Endomycorrhizal fungi: Glomus intraradices, Glomus mosseae, Glomusaggregatum, Glomus clarum, Glomus deserticola, Glomus etunicatum,Gigaspora margarita, Gigaspora brasilianum, Gigaspora monosporum.

Ectomycorrhizal fungi: Rhizopogon villosullus, Rhizopogon luteolus,Rhizopogon amylopogon, Rhizopogon fulvigleba, Pisolithus tinctorius,Laccaria bicolor, Laccaria laccata, Scleroderma cepa, Sclerodermacitrinum, Suillus granulatas, Suillus punctatapies.

Trichoderma fungi: Trichoderma harzianum, Trichoderma konigii

Bacteria: Bacillus subtillus, Bacillus licheniformis, Bacillusazotoformans, Bacillus megaterium, Bacillus coagulans, Bacillus pumlis,Bacillus thuringiensis, Bacillus stearothermiphilis, Paenibacilluspolymyxa, Paenibacillus durum, Paenibacillus florescence, Paenibacillusgordonae, Azotobacter polymyxa, Azotobacter chroococcum, Sacchromyccscervisiae, Streptomyces griseues, Streptomyces lydicus, Pseudomonasaureofaceans, Deinococcus erythromyxa.

BMF char was produced using a biomass fractioning system and madehydrophilic via methods of the present invention. The BMF char wassaturated with the above compost mixture in open air for 3 days. Anuptake greater than 50% of the dry BMF char weight was observed. Thecolonization of BMF char derived from corn is shown in the SEMmicrograph show in FIG. 7 b. Various microorganisms are evident in themicrograph. A comparison of BMF char from a similar derivation butwithout exposure to microorganisms is shown in FIG. 7 a.

Modifications may be made by those skilled in the art without affectingthe scope of the invention.

Although the invention is described above in terms of various exemplaryembodiments and implementations, it should be understood that thevarious features, aspects and functionality described in one or more ofthe individual embodiments are not limited in their applicability to theparticular embodiment with which they are described, but instead can beapplied, alone or in various combinations, to one or more of the otherembodiments of the invention, whether or not such embodiments aredescribed and whether or not such features are presented as being a partof a described embodiment. Thus, the breadth and scope of the presentinvention should not be limited by any of the above-described exemplaryembodiments.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as meaning “including, without limitation” or the like; the term“example” is used to provide exemplary instances of the item indiscussion, not an exhaustive or limiting list thereof; the terms “a” or“an” should be read as meaning “at least one,” “one or more” or thelike; and adjectives such as “conventional,” “traditional,” “normal,”“standard,” “known” and terms of similar meaning should not be construedas limiting the item described to a given time period or to an itemavailable as of a given time, but instead should be read to encompassconventional, traditional, normal, or standard technologies that may beavailable or known now or at any time in the future. Likewise, wherethis document refers to technologies that would be apparent or known toone of ordinary skill in the art, such technologies encompass thoseapparent or known to the skilled artisan now or at any time in thefuture.

The presence of broadening words and phrases such as “one or more,” “atleast,” “hut not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent. Additionally,the various embodiments set forth herein are described in terms ofexemplary block diagrams, flow charts and other illustrations. As willbecome apparent to one of ordinary skill in the art after reading thisdocument, the illustrated embodiments and their various alternatives canbe implemented without confinement to the illustrated examples. Theseillustrations and their accompanying description should not be construedas mandating a particular architecture or configuration.

1. A method for the production of an agent for enhancing soil growth,comprising: grinding a biomass feedstock to produce ground biomassparticles; subjecting the ground biomass particles to sequential orconcurrent ramps of temperature and pressure shocks; selectivelycollecting at least one volatile component as it is released from theground biomass particles; collecting a last remaining nonvolatilecomponent comprising BMF char; rendering a surface of the BMF charhydrophilic after collecting the BMF char by removing adsorbed gaswithin char pores by introducing a water solution containing solubleplant nutrients; exposing the BMF char to microorganisms after renderingthe surface hydrophilic; and then adding the BMF char to soil afterexposing the BMF char to microorganisms.
 2. The method of claim 1,wherein the biomass particles are ground to a diameter between about0.001 inch and about 1 inch.
 3. The method of claim 1, furthercomprising dispensing the ground biomass particles into thin sheetswhose total thickness is a multiple of the ground biomass particlediameter before subjecting the ground biomass particles to sequential orconcurrent ramps of temperature and pressure shocks wherein the multipleis any real number in the range of 1 to
 30. 4. The method of claim 1,wherein the biomass feedstock is used to produce different BMF charsbased on a composition of the biomass feedstock.
 5. The method of claim1, wherein the pressure shocks vary in magnitude from 0.2 MPa to 10 GPa,wherein an admixture of pressure shocks of differing magnitudes iscombined with pressure shocks applied over a range of times.
 6. Themethod of claim 1, wherein the temperature ramp includes a sufficientlyhigh temperature to create a nonvolatile carbonaceous material withinthe ground biomass particles.
 7. The method of claim 1, wherein thepressure shocks increase thermal conductivity of formed nonvolatilecarbonaceous material within the ground biomass particles.
 8. The methodof claim 1, wherein the temperature ramps and pressure shocks areconducted in an atmosphere containing a supercritical fluid.
 9. Themethod of claim 1, wherein the pressure shocks decrease the effectivedensity of the ground biomass particles.
 10. The method of claim 1,wherein a pH of the BMF char is controlled via pH adjustment agents. 11.The method of claim 1, wherein the BMF char is activated.
 12. The methodof claim 1, wherein a pH of the soil is modified to accept the additionof BMF char.
 13. The method of claim 1, wherein microorganisms includemembers of at least one of fungi, bacteria or archaea.
 14. The method ofclaim 13, wherein fungi are members of the phyla Glomeromycota.
 15. Themethod of claim 1, wherein the BMF char contains glomalin structures.16. A method for the production of an agent for enhancing soil growth,comprising: grinding a biomass feedstock to produce ground biomassparticles having a diameter between about 0.001 inch and about 1 inch;dispensing the ground biomass particles into thin sheets whose totalthickness is a multiple of the ground biomass particle diameter;subjecting the ground biomass particles to sequential or concurrentramps of temperature and pressure shocks; selectively collecting atleast one volatile component as it is released from the ground biomassparticles; collecting a last remaining nonvolatile component comprisingBMF char; rendering a surface of the BMF char hydrophilic aftercollecting the BMF char by removing adsorbed gas within char pores byintroducing a water solution containing soluble plant nutrients; addingthe BMF char to soil after rendering the surface hydrophilic; and thenexposing the BMF char to microorganisms.